Preparation of Composite Layup
Before curing, composite materials are laid up in the desired configuration, with layers of reinforcing fibers impregnated in the polymer matrix.
Heating Phase
The composite structures or parts are placed in bags under a vacuum and within an industrial oven for the curing process.
Heating is initiated to elevate the temperature and activates the curing reactions within the resin.
Curing Temperatures
Curing temperatures can vary based on the specific resin system being used. Epoxy resins commonly used in aerospace composites may require curing temperatures ranging from approximately 120°C to 200°C (248°F to 392°F) with temperature uniformity requirements up to +/-3°C (+/-5°F).
Soaking or Dwell Time
The structure is held at the curing temperature for a specified duration, allowing the resin to flow, cross-link, and cure thoroughly. The soaking time ensures uniform curing throughout the composite material. The specific time is dictated by the resin system and is often specified by the material manufacturer.
Cooling Phase
After the soaking period, the composite structure is gradually cooled to room temperature. Controlled cooling helps prevent thermal stresses and ensures the preservation of the desired material properties.
Application for Aerospace Industry
Controlled curing is critical in aerospace applications to ensure that composite components meet stringent performance and safety standards. Manufacturers follow carefully designed curing cycles, considering factors such as resin type, composite thickness, and part geometry, to produce high quality and reliable composite structures for use in aircraft.
